Improper Input Validation vulnerability in Apache Tomcat Native, Apache Tomcat.
CVE-2026-24734 is a high-severity improper input validation vulnerability in Apache Tomcat Native from Apache, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected Apache Tomcat Native versions: 1.1.23 through 1.1.34; 1.2.0 through 1.2.39; 1.3.0 through 1.3.4, and others listed below. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.59% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Tomcat to 9.0.115 or 10.1.52 or 11.0.18, whichever matches your release line, or a later version.
- Update Tomcat Native to 1.3.5 or 2.0.12, whichever matches your release line, or a later version.
- Read the advisory on lists.apache.org for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Apache | Apache Tomcat Native | 1.1.23 through 1.1.34; 1.2.0 through 1.2.39; 1.3.0 through 1.3.4; 2.0.0 through 2.0.11 | Not stated |
| Apache | Apache Tomcat | 11.0.0-M1 through 11.0.17; 10.1.0-M7 through 10.1.51; 9.0.83 through 9.0.114 | Not stated |
| Red Hat | Red Hat Enterprise Linux 10 | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 9 | Not specified in the record | Not stated |
| Red Hat | Red Hat JBoss Web Server 6.2.1 | Not specified in the record | Not stated |
| Red Hat | Red Hat JBoss Web Server 6.2 on RHEL 10 | Not specified in the record | Not stated |
| Red Hat | Red Hat JBoss Web Server 6.2 on RHEL 8 | Not specified in the record | Not stated |
| Red Hat | Red Hat JBoss Web Server 6.2 on RHEL 9 | Not specified in the record | Not stated |
| Red Hat | Red Hat Hardened Images | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 6 | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 7 | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 8 | Not specified in the record | Not stated |
| Red Hat | Red Hat JBoss Web Server 5 | Not specified in the record | Not stated |
| Apache | Tomcat | 9.0.83 up to, but not including, 9.0.115; 10.1.1 up to, but not including, 10.1.52; 11.0.1 up to, but not including, 11.0.18; 10.1.0; 11.0.0 | 9.0.115, 10.1.52, 11.0.18 |
| Apache | Tomcat Native | 1.3.0 up to, but not including, 1.3.5; 2.0.0 up to, but not including, 2.0.12 | 1.3.5, 2.0.12 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- NoneNo data is disclosed.
- Integrity
- HighData or code can be modified at will.
- Availability
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.5 | High | NVD |
| CVSS 3.1 | 7.4 | High | CISA (ADP) |
| CVSS 3.1 | 7.4 | High | CNA |
Official description
Improper Input Validation vulnerability in Apache Tomcat Native, Apache Tomcat. When using an OCSP responder, Tomcat Native (and Tomcat's FFM port of the Tomcat Native code) did not complete verification or freshness checks on the OCSP response which could allow certificate revocation to be bypassed. This issue affects Apache Tomcat Native: from 1.3.0 through 1.3.4, from 2.0.0 through 2.0.11; Apache Tomcat: from 11.0.0-M1 through 11.0.17, from 10.1.0-M7 through 10.1.51, from 9.0.83 through 9.0.114. The following versions were EOL at the time the CVE was created but are known to be affected: from 1.1.23 through 1.1.34, from 1.2.0 through 1.2.39. Older EOL versions are not affected. Apache Tomcat Native users are recommended to upgrade to versions 1.3.5 or later or 2.0.12 or later, which fix the issue. Apache Tomcat users are recommended to upgrade to versions 11.0.18 or later, 10.1.52 or later or 9.0.115 or later which fix the issue.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Input Validation
The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.
How developers prevent this class of flaw
- Consider using language-theoretic security (LangSec) techniques that characterize inputs using a formal language and build recognizers for that language. This effectively requires parsing to be a distinct layer that effectively enforces a boundary between raw input and internal data representations, instead of allowing parser code to be scattered throughout the program, where it could be subject to errors or inconsistencies that create weaknesses.
- Use an input validation framework such as Struts or the OWASP ESAPI Validation API. Note that using a framework does not automatically address all input validation problems; be mindful of weaknesses that could arise from misusing the framework itself (CWE-1173).
- Understand all the potential areas where untrusted inputs can enter the product, including but not limited to: parameters or arguments, cookies, anything read from the network, environment variables, reverse DNS lookups, query results, request headers, URL components, e-mail, files, filenames, databases, and any external systems that provide data to the application. Remember that such inputs may be obtained indirectly through API calls.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Advisories
- lists.apache.org/thread/292dlmx3fz1888v6v16221kpozq56gmlIssue Tracking, Mailing List
Other references
- access.redhat.com/errata/RHSA-2026:19054
- access.redhat.com/errata/RHSA-2026:26323
- access.redhat.com/errata/RHSA-2026:36790
- access.redhat.com/errata/RHSA-2026:5611
- access.redhat.com/errata/RHSA-2026:5612
- access.redhat.com/errata/RHSA-2026:6569
- access.redhat.com/errata/RHSA-2026:8334
- access.redhat.com/security/cve/CVE-2026-24734
- bugzilla.redhat.com/show_bug.cgi?id=2440426
- security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-24734.json
Other vulnerabilities in Apache Tomcat Native
- 7.4 High severity
- 9.1 Critical severity
- 7.5 High severity
- 9.1 Critical severity
Recent Improper Input Validation vulnerabilities
- 7.5 High severity
- 7.5 High severity
- 8.2 High severity
- 7.5 High severity
- 7.5 High severity
- 9.1 Critical severity
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